Move set require to file where it is used.

myronmarston · myronmarston · commit 322d272634e4 · 2014-02-24T14:28:31.000-08:00
diff --git a/lib/rspec/core.rb b/lib/rspec/core.rb
@@ -1,4 +1,3 @@
-require 'set'
 require 'time'
 require 'rbconfig'
 
diff --git a/lib/rspec/core/configuration_options.rb b/lib/rspec/core/configuration_options.rb
@@ -1,5 +1,6 @@
 require 'erb'
 require 'shellwords'
+require 'set'
 
 module RSpec
   module Core
